That compares with 67.2 million viewers for the candidates' Oct. 3 faceoff and 65.6 for the debate on Oct. 16.

Nielsen notes that Monday's debate "was up against two sporting events — Monday Night Football on ESPN, which had 10.7 million people tuning in and Game 7 of [baseball's National League championship series] on FOX, which had 8.1 million people watching."